The present invention relates to an image forming apparatus such as an electronic copier, a printer, a facsimile, or a complex machine.
The present invention relates to an image forming apparatus in which of a transfer the developing units and carrier units in the image making units are individually independently attachably and detachably mounted to an image forming apparatus body, and toner images formed on the image carriers in the image making units are transferred to a transfer material.
However, for the developing units and the carrier units to be individually attachable to and detachable from the image forming apparatus body, it is necessary to provide a guide member for a developing unit of each image making unit and another guide member for a carrier unit of each image making unit, thus resulting in an increase in number of components of the image forming apparatus, with an unavoidable increase in cost therefor, as a disadvantage.
It is an object of the present invention to provide an image forming apparatus of the above-noted type with the disadvantage eliminated.
The present invention relates to an image forming apparatus in which image making unit provided with developing units having at least developing devices and carrier units having image carriers for toner images to be formed thereon by the developing devices and supports for supporting the image carriers are disposed at least two along a moving direction of a transfer material, the developing units and the carrier units of the image making unit are individually independently attachably and detachably mounted to an image forming apparatus body, and the toner images formed on the image carriers of the image making unit are transferred to the transfer material.
A first aspect of the present invention provides an image forming apparatus of the above-noted type, wherein a common guide member adapted, when a carrier unit of one image making unit of two image making unit neighboring each other and a developing unit of the other image making unit are attached to or detached from the image forming apparatus body, for guiding the carrier unit and the developing unit respectively is provided.
According to a second aspect of the invention, preferably, at least part of a carrier unit of one image making unit of the two image making unit neighboring each other that is positioned upstream in a transfer direction of the transfer material is positioned under a developing unit of the other image making unit positioned downstream in the transfer direction of the transfer material.
A third aspect of the present invention provides an image forming apparatus according to the second aspect, wherein, preferably, the carrier unit of the image making unit of the two image making unit neighboring each other that is positioned upstream in the transfer direction of the transfer material is supported by a part of the guide member lower than the developing unit of the image making unit positioned downstream in the transfer direction of the transfer material.
Further, a fourth aspect of the present invention provides an image forming apparatus according to the third aspect, wherein, preferably, the carrier unit of the image making unit of the two image making unit neighboring each other that is positioned upstream in the transfer direction of the transfer material is supported by the guide member, in a condition suspended by the guide member, and the developing unit of the image making unit positioned downstream in the transfer direction of the transfer material is supported by the guide member, in a condition fitted to an upper part of the guide member.
A fifth aspect of the present invention provides an image forming apparatus according to the fourth aspect, wherein, preferably, the carrier unit is suspended by the guide member at two points, and an image carrier of the carrier unit is positioned under both suspending parts.
A sixth aspect of the present invention provides an image forming apparatus according to the fifth aspect, wherein, preferably, the carrier unit is suspended at the two points spaced from each other in a horizontal direction of the guide member, and a center of gravity of the carrier unit is positioned under an area between the both suspending parts.
A seventh aspect of the present invention provides an image forming apparatus according to any of the first to sixth aspects, wherein, preferably, the carrier unit and the developing unit are attached to or detached from the image forming apparatus body, in conditions supported by the guide member, by pushing substantially in a horizontal direction relative to the image forming apparatus body or by drawing out, and when the carrier unit is being attached to or detached from the image forming apparatus body, in order for a moment due to an own weight of the carrier unit not to act on the carrier unit, the carrier unit is supported in a horizontal condition by the guide.
An eighth aspect of the present invention provides an image forming apparatus according to any of the first to seventh aspects, wherein, preferably, the carrier unit and the developing unit are attached to or detached from the image forming apparatus body, in conditions supported by the guide member, by pushing substantially in a horizontal direction relative to the image forming apparatus body or by drawing out, and when the developing unit is being attached to or detached from the image forming apparatus body, in order for a moment due to an own weight of the developing unit to act on the developing unit, the developing unit is supported by the guide member, and an auxiliary guide member for preventing the developing unit from being inclined by the moment, when the developing unit is being attached to or detached from the image forming apparatus body, is provided.
A ninth aspect of the present invention provides an image forming apparatus according to any of the first to eighth aspects, wherein, preferably, toner transfer pumps for transferring toners to the developing devices of the image making unit respectively and toner accommodation containers connected via conduits to the toner transfer pumps and accommodating toners to be sent to the toner transfer pumps are provided, and the conduits are at least partially disposed on the guide member.
Other objects and features of this invention will become apparent from the following description with reference to the accompanying drawings.